Hezbollah-backed Sunni billionaire businessman Najib Mikati clinched on Tuesday the backing of a majority of MPs in order to be appointed as Lebanon's new prime minister, according to an AFP count.
Mikati, 55, received the backing of 65 of parliament's 128 MPs who have been meeting since Monday with President Michel Sleiman after Hezbollah brought down the unity government of Western-backed Saad Al-Hariri.
Sleiman was expected to appoint Mikati to head the new government later on Tuesday after wrapping up his consultations with parliamentary groups.
His probable appointment has sparked widespread anger within the Sunni community as thousands of protesters gathered in Lebanon's Sunni bastion of Tripoli on Tuesday for a "day of rage".
The demonstrators converged on a main square of the seaport city carrying placards that read "Iran's project will not go through Tripoli", "No to backstabbing" and "Mikati, the Shia dog."
They angrily accused Iranian-backed Hezbollah of imposing Sunni tycoon Najib Mikati to head the next government.
According to an AFP count, Mikati, who himself hails from Tripoli, on Tuesday clinched the backing of a majority of MPs needed to become prime minister.
"I am a Sunni Muslim and I refuse to allow anyone to impose their candidate for premiership on our community," said Um Khodr, 50. "We will remain in the streets until the traitor Mikati leaves the post."
Rana Fatfat, a 35-year-old attorney, said she was taking part in the protest to denounce "Hezbollah's arrogance" toward the Sunni community.
"They are taking us for idiots," she said. "We will fight them through sit-ins and peaceful protests because we cannot match their military might."
Schools and many stores shut down in Tripoli and surrounding areas amid heavy security.
Similar protests were planned in other regions, including in Beirut and the mainly Sunni southern coastal city of Sidon.
About 150 protesters blocked the main highway leading to Sidon with burning tyres. Demonstrators also burned tyres in the western Beirut neighbourhood of Tareek Al-Jadidah.
Sunni MPs called for the protests on Monday, accusing Hezbollah of having staged a "coup" as it became clear the Shia party and its allies had secured enough votes in the 128-seat parliament to impose Mikati to head the next government.
Mikati's candidacy has angered the Sunni community who see it as a bid by Hezbollah to marginalise outgoing premier Saad Al-Hariri -- Lebanon's most popular Sunni leader -- and essentially take control of the government.
Protests broke out on Monday in mainly Sunni regions, including Tripoli, Sidon and several west Beirut neighbourhoods with demonstrators burning tyres and chanting "Sunni blood is boiling!"
There were no reports of injuries, but the US embassy near Beirut issued a warning to its citizens to take safety measures.
"The embassy urges US citizens to remain alert to local security developments and to be vigilant regarding their personal security," it said in a statement.
Hezbollah on 12 January brought down Prime Minister Hariri's Saudi- and Western-backed government after a long-running standoff over a UN-backed probe into the 2005 assassination of ex-premier Rafiq Al-Hariri, Saad's father.
The group has said it believes members of the party will be implicated by the Netherlands-based Special Tribunal for Lebanon, which it has denounced as part of a US-Israeli conspiracy.
Washington, which considers Hezbollah a terrorist organisation, has expressed "great concerns" at the likelihood of the party playing a major role in the new government.
Although Hezbollah has said its coalition would seek to include its rivals in the new government, Hariri has ruled out joining a cabinet controlled by the Shia party.
Hariri's coalition controlled a majority in parliament but with Mikati leaving the coalition and influential Druze leader Walid Jumblatt also siding with Hezbollah, his camp lost its majority.